The invention relates generally to communications and more particularly to a system and method for using a quality-indication signal added to a transmitted signal in a communication system, and used by the receiving end, in conjunction with multiple antenna elements. The receiver can use a separation process known as spatial filtering, or also referred to herein as smart antenna.
Broadband networks having multiple information channels are subject to certain types of typical problems such as inter-channel interference, a limited bandwidth per information channel, inter-cell interference that limit the maximum number of serviceable users, and other interference. The usage of smart antenna techniques (e.g., using multiple antenna elements for a separation process known as spatial filtering), at both ends of the wireless communications channels, can enhance spectral efficiency, allowing for more users to be served simultaneously over a given frequency band.
Power-control signaling is another technique used to minimize inter-channel interference and increase network capacity. For example, mobile communication standards include a high rate, continuous, power-control signaling to ensure that mobile communication devices do not transmit too much or too little power. More specifically, based on the strength of the signal sent from the communication device and received at the basestation, the basestation sends a power-control signal to the mobile communication device indicating whether the communication device should increase or decrease the total power of its transmitted signal. The transmission rates for each value of the power-control signals are, for example, 1.25 ms for cdmaOne (IS-95)/CDMA2000, and 0.66 ms for WCDMA.
The known uses of power-control signaling have been limited only to adjusting the total power of the signal transmitted from the communication device. Next generation communication devices, however, can use multiple antenna elements (also referred to herein as a “smart antenna”) for a separation process known as spatial filtering. Thus, a need exists for an improved system and method that can combine the advantages of power-control signaling with the advantages of smart antennas.